Sima Tonio to Cueva Canuela
Tuesday, 12 June 2012

Having arrived in Matienzo and having had a few days of rain, it seemed from our descriptions available that this traverse would be the best wet weather option as it is supposedly unaffected by heavy rain.

As with finding the entrances for most of the caves we visited or tried to visit in the Ason Gorge, we had problems from the start with descriptions and GPS co-ordinates not being very helpful, and after spending many hours wandering the mountain sides following incorrect co-ords we decided to try and write more useful route descriptions, and GPS the entrances.

The route to Sima Tonio (on the way up to Cueto) appears to have had a new farmers track bulldozed into the side of the hillside, but this actually makes the route finding slightly easier.


Leave the car in Socueva, opposite the little chapel. Follow the tarmac road uphill out of the village following signs to Ermita (Hermitage). After 10-15 minutes there is a fork in the road with the right branch signposted to Ermita or a way on straight ahead. Carry on straight ahead and soon a wide rocky and muddy track turns right where the tarmac ends. Take this track, which very quickly turns into a footpath (old donkey track). The path continues up the hill in a zig-zag fashion until at the top of the climb, the path passes through a small col, and reaches a stone cabin.

From here a wide rocky and very muddy track continues on and heads round to the left (this track appears to be newly bulldozed and is not mentioned in any of the descriptions we previously read). This point overlooks a shallow dry valley ahead, and looking ahead it is possible to see a number of stone cabins on the hillside on the opposite side of this valley. For a frame of reference on the walk, the entrance lies in a field just below the last cabin visible from this point. The track now contours round the hill to the left, slowly climbing and following the route of the old Cueto walk-in path (now buried under the new track). The track follows the hillside all the way round to above the afore-mentioned stone cabins, passing through crude barbed-wire gates, and passing the turn off left for the path to Cueto. The track now winds around some large dolines and soon reaches the last cabin (if another gate is reached in the track, and then the track starts to head down a bleak hill with no visible cabins, then you have gone too far).

The last cabin is to the right, and slightly downhill of the track. Here, leave the track and follow a small footpath down along-side the dry-stone wall immediately after the cabin. This leads down to a water fountain and trough in some small trees, which is useful for soaking ropes. Climb over the wall where possible (brambles abound here) and into the field below the cabin. The entrance is situated just to the West of a small depression full of trees and bushes. Footpaths circle this depression and lead up to the left hand side where the entrance is a slot in the side of some outcropping limestone (it is hidden from the path by trees). The walk should take around 1.5 hours assuming no problems.

The GPS co-ordinates we used were accurate, and took us to the depression mentioned above:

UTM (WGS84) 30T 449120m 4790390m


The Tonio ‘ Canuella traverse is a relatively straightforward through trip that should not require a reccie of the bottom entrance as long as a description is taken. It consists of a series of pull-through abseils down a series of 16 pitches that intersects a large “horizontal passage of Cueva Canuela at around 280m depth, where scrambling, climbing and walking through impressively large phreatic galleries reaches the exit approx. 400m lower than the Tonio entrance.

The entrance pitch to Tonio descends the small surface slot into a chamber that is not for the arachnophobe!! Large spindly spiders and egg-sacks are plastered to the walls and surround the next pull-through bolts. Holly moved quickly through this section, not looking at any walls, after I explained the spider “situation (It might be an understatement to say that Holly isnt too fond of spiders). After this the cave becomes nice. Two short pitches lead to the head of a 48m shaft where an obvious pendulum swings off into a window before the bottom. A climb up fixed wires here leads to another 3 pitches, the second one being down a fairly tight slot, and the third down a sloping tube that shouldnt be free-climbed due to a large drop below. This drop is not descended ‘ the way on is not immediately obvious but ducking under rock to the left gains a fixed line of dubious antiquity that crosses another deep pot and swings into yet another parallel shaft series. Two very small pitches follow to the top of a 55m shaft with yet another pendulum off before the bottom. This pendulum gains a large obvious window with a pitch immediately on the opposite side. Most of the remaining pitches follow in quick succession up to a meander that precedes the final pitch of Sima Tonio. This pitch has an entertaining take off due to its location in a little window in the roof of a massive horizontal passage near the end of Cueva Canuela – acrobatic fun is guaranteed here.

Now the cave is mostly “stompy passage to the exit (The largest part of the cave can be visited first by heading up the boulder slope into the massive Salle Olivier Gillaume, the top of the bolder pile appears to be in the widest part ‘ and is like being on top of a mountain on a vary dark night ‘ my light didnt reach the walls).
The next part can be confusing amongst the boulders in the large passage, and a compass and survey were very helpful to us. The way on descends from the foot of the last pitch, steeply down the boulder slope to the East. Once down the steepest part, there is a way on in the North wall that is not immediately obvious, until you are almost upon it. Once in the passage, it is fairly large and descends steeply Northwards, with a rope climb along the way (compass useful for this). From here the way continues through massive sword-like stalagmites hanging from far above, then passes a canyon in the floor with an audible stream below. The way continues along the massive easy passage (with occasional bouldery climbs), ignoring side passages, the largest of which is down a climb to the left. The passage ends abruptly at a large balcony overlooking the Sala del Vivac.

The way on is just back from the edge of this balcony, on the left (when facing towards the edge). A short slope leads upwards to the edge of a large pit. The way on was described in our description as a roped climb up to the right, that skirts this hole ‘ this was not immediately obvious and we spent about 40mins looking for a rope before deciding that a slippery exposed free-climb on the edge of the pit best matched our description, deciding this must be it “sans rope. At the top there was a hanger where the rope had obviously been removed from. The way on continues, getting smaller before a climb up past boulders re-gains the large passage. Continuing North, ignoring side passages, a large junction is reached at the bottom of a climb. Apparently there are a few ways to the exit from here but to the right up a climb (following reflectors) leads into a massive impressive flat floored passage, that is followed to the final pitch.

From the base of the final pitch, following the passage to the East leads towards the exit. This passage is a GINORMOUS phreatic passage, especially impressive when daylight can be seen nearer the end. A final traverse is crossed not far from the end on fixed lines. The entrance is much smaller than the preceding phreas, but still an impressive opening far up above the road in the Bustablado valley.


On leaving the cave, the path descends steeply down the hill into the woodland below (this is a fairly easy walk as you are fairly close to the road, which can be seen from the entrance).
When we did this, we lost the small path in the woods, so we carried on down and left through the woods, until we saw a clearing/field (with power lines) through the trees (West of the forest). Once in this field, heading West leads to a cabin, where the field opens up more, and heading downhill following a now obvious muddy track leads down to the river. The river can be forded in a few places, and once across, head uphill to the right (East) towards the farmhouse on the other side of the road (There were enthusiastic dogs barking at us from this farm for long before we reached it). Opposite the farm is a gate which allows an exit onto the road. To walk back to Socueva, turn right to Arredondo, where a right turn leads back up the hill to the car. The walk back is quite long on tarmac, and a second shuttle car may be a good option for parties with more than one vehicle.


-2 x 50m ropes should be fine – apart from the two pendulum pitches (max 38m abseil), all the pitches are shorter than 25m so can be done with one rope.
-A few maillons and slings would be useful just in case ‘ we had to leave a little gear at a pitch head due to the condition of the in-situ gear.
-Survey/rigging topo and cave description.
-A compass is not essential but is useful in the large bouldery passages.

An excellent wet weather through trip, that is fairly straightforward, with very impressive formations and huge passages near the Canuela entrance. 5-8 hours should be enough time for the traverse, plus 1.5 hours for the walk in (assuming no problems with finding the entrance), and 1.5 hours for the return walk (with a second shuttle car this could be 30mins).
This was also a nice “warm-up cave before doing some of the larger through trips in the Ason Gorge.